Achiwa in J.A.C.S., 98, 8265 (1976) describes BPPM [(2S,4S)-N-butoxycarbonyl-4-diphenyl-phosphino-2-diphenylphosphinomethyl-p yrrolidine] and the use of this compound in the form of a rhodium complex as a catalyst for asymmetric hydrogenation.
Achiwa in papers in Tetrahedron Letters, No. 50, 4431 (1977) and Chemistry Letters, 297-998 (1978) has described the asymmetric hydrogenation of ketopantolactons with a rhodium complex of BPPM.
Finally, Knowles et al. in "Fundamental Research in Homogeneous Catalysis", Vol. III, pages 537-548, particularly page 542, Editor: Tsutsui Publisher, Plenum Press, New York, refers erroneously to phosphines corresponding to formula I herein where R.sup.1 is --SO.sub.2 --CH.sub.3. However, from the content of the text it is clear that the pivaloyl group was intended.